The invention relates generally to missile guidance systems, and more particularly to such a system having an active optical tracking subsystem.
Missile guidance systems are in general of two basic classes. The first class is the on board guidance system which is an integral part of the control system located within the missile. The second is the independent system which is located away from the missile, however tracks a target and, utilizing telemetry or other means, sends error correction signals to the missile control system.
The first class, or on board system, is of interest in this disclosure. Commonly referred to as a "seeker", the system performs several functions including acquisition of a target upon command; tracking of the target after acquisition and during missile flight, and derivation and reprocessing of the data necessary for the guidance subsystem to execute control of the missile flight.
In considering, for example, the air-to-air missile, existing optical missiles utilize passive seekers generally operating in some portion of the infrared spectrum. This is typically within the 2-5 micron band. Guidance or seeker data is derived from target radiation, thus allowing reasonable tracking of an appropriate target.
At least one countermeasure system has been devised to thwart the passive optical seeker in a very effective and inexpensive manner. This involves the release of radiation sources by the target which are in the same spectral region as the target infrared source but much more intense. This causes the missile seeker to track and destroy a harmless radiation source at a safe distance from the target.
Active optical systems have been considered. However, a substantial difficulty has occurred in designing a system which is small, lightweight, inexpensive, and still reliable enough to use in a missile system. The invention disclosed herein solves these problems and by utilizing the laser provides a highly accurate tracking system.